馬脚を露わす

ばきゃくをあらわす

to reveal one's true nature

Meanings

also 馬脚を現す · 馬脚を表す

  1. expression, godan verb, idiom to reveal one's true nature; to show one's true colours; to give oneself away; to be exposed (of a lie, etc.)

Its kanji

In sentences

彼かれもついに馬脚ばきゃくを露あらわした。 He has finally shown his true colors. #98803